Zombie Games by Kristen Middleton (Origins)

Seventeen year old Cassandra Wild thought living in the chaos of her mother's home daycare and dealing with her developing feelings for Bryce, her new Martial Arts' instructor, was a struggle, until the night her world turned upside down. When an untested vaccine kills more than just a rampant flu virus, Cassie learns how to survive in a world where the dead walk and the living...run!